🚀 go-pugleaf

In article <C0LJ17.LJu@newcastle.ac.uk>, w.p.coyne@newcastle.ac.uk writes:
|>    The paper says "Jerison discovered that repiles were
|> small-brained 300 million years ago and remain so today.  
|> His plot (logarithmic) of brain size against body size for
|> every known reptile species, extant and extinct, produced 
|> a straight line.  The
|> dinosaurs, many of which had much bigger bodies than living 
|> reptiles, fall
|> squarely on this line, belying the myth that they lumbered to 
|> extinction because they were especially stupid."

Hmm, this seems to contradict what I have seen in other sources.
For theropod dinosaurs, at least, the regression line I have seen falls
slightly above that for typical reptiles.

Of course it is true that if you lump all dinosaurs together you get a result
that is essentially the same as for other reptiles.
[That is the large brains of theropods and the small brains of sauropods cancel
each other out].

|>                 -----------------------
|>   You say birds have brains almost as large as mammals.  According
|> to some of Jerison's work there is actually a massive overlap between
|> the brain size (relative to body size) of mammal species and of bird 
|> species

Yep, that there is.  But, given the spread around the averaged regression line,
this is not quite the same thing as saying they have the *same* brain size.
I do believe that the avian regression line is slightly below that of mammals.

An interesting note - the largest brained dinosaurs (Stenonychosaurus and its
close relatives) actually fall in the lower avian range (That is the relative
brain size is above that of the smallest-brained birds).

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Stanley.Friesen@ElSegundoCA.ncr.com